dipropyl 2-methylidenebutanedioate 1-Propene-2,3-dicarboxylic acid dipropyl ester 2-Methylenebutanedioic acid dipropyl ester 2-Methylenesuccinic acid dipropyl ester Dipropyl 1-propene-2,3-dicarboxylate Dipropyl itaconate Itaconic acid dipropyl ester Butanedioic acid, 2-methylene-, 1,4-dipropyl ester